A tool to measure depth to water down a well

[lukeyblue]

Hello all,

I am currently working for an NGO in Mongolia and getting local herder people to measure the depth to water in their shallow wells (<5m) on a regular basis. We are in the design phase at the moment and trying to come up with a simple tool to meausre the depth to water, however we are slightly stuck with the design and i have come here in the hope someone on these forums might be able to help us a little?
What we were thinking is a simple tape measure (5m) that has a weight at the end to keep the tape straight and vertical but to also act as a float, so that when they reach the water the line will go slack because the weight/float will be supported by weight of the water, and then they can pull the tape tort to get then get depth of water and read it from the tape measure.
However it is good in principle, but we are struggling to find a weight that is heavy enough that will also work as a float, and then also how to attach the weight to the end of the tape measure. The only way we have found so far is with the tape end of a surveyors tape measure, so we could perhaps clip something on... however lots of them are flimsy and break easily, and we have not found any that come only in 5 or 10m length. Also, we find when we have attached a weight, it does not take long for the end of the tape to fray and end up breaking off the clip at the end of the tape measure.

We are really stuck, so if you have any advice on what we could do, or any products you think that we could buy and then get shipped over here would be greatly appreciated.

Many thanks,
Luke

 

[CaptainCaveman289]

Knotted piece of string with a tennis ball on the end, count the knots.
No need to over complicate things.

 

[mattylad]

The above post sums it up, K.I.S.S.....

BTW - the weight can be below a float and the float - well floats.
Measure from the top to the waterline on the float.

 

[taz123]

String with a float attached above a weight and an elastic band above the float. You can replace the elastic band with a piece of string tied around the main string.

Lower the weighted end into the water, the float pushes the elastic band up the string and that's where it will stay whilst retrieving..

 

[CaptainCaveman289]

The above post sums it up, K.I.S.S.....

My sentiments exactly, it's dirt cheap, quick, can be used in the dark or by someone who can count but not read.
An empty bucket on a knotted line will also serve the same purpose, and if it's a well they almost certainly have a bucket.

Are you trying to provide a solution to a problem or sell somebody something?

Whats an NGO?

 

[Jackrae]

All of the above require subtraction skills - however simple they may be.

Why not use a suitable length of cane to which is attached a length of cord sufficient to permit the free end of the cane to reach the deepest depth of the well. To the free end of the cane fix a weight sufficient to make the cane sink. Lower the weighted cane until the cord goes slack (the cane end is touching the bottom of the well. Withdraw cane and observe the length of the wetted portion.

If a single cane is of insufficient length simply tie two or more together with short loops of twin so making, in effect, a "foldable" long cane.

Super simple and low tech with no subtraction mathematics required.

 

[mattylad]

Now that idea just sound stupid!

How do they ascertain the depth of the water by a cane? They have to measure it. does that not require simple maths skills?

You seem to ignore that the purpose here is measurement, and that requires simple maths skills.

A tennis ball on the end of a string, then a free running weight that when lowered will sink to the bottom then noting the marker - slowly release the string allowing the ball to float will then show further markers that can be counted until it reaches the surface and stops.

If the string has markers on then they just need to read the number and not do any maths.

Simple, can be easily stored and wont be used with any tomato plants

 

[Jackrae]

I see diplomacy is alive and well

On the basis that the OP actually wants "depth to water" ie the air space from well top to water surface, then the tennis ball and similar techniques are indeed what's required

However, if he actually wants water depth, then I would tend to favour techniques that measure the primary variable (depth from water surface to well bottom).

 

[AnerleyBoy]

Lots of good ideas above.

If the measuring system doesn't have to be portable but can be installed in the well, how about -
a lightweight pipe of length appropriate to the well is capped at both ends;
the pipe is fixed vertically in loose brackets on the well shaft wall;
the brackets retain the pipe but allow it to slide up and down easily;
the pipe sits in the water and floats up and down as the water level changes;
the top of the pipe moves against a fixed scale at the top of the well shaft;
the scale can be fixed inside the well shaft or above it;
the scale can be calibrated in any suitable units at installation;
the pipe can be 32mm plastic waste or bamboo or ...;
extra buoyancy can be attached to the bottom of the pipe, if necessary;
the extra buoyancy could be plastic milk jugs, footballs, goatskins or ...;
my guestimate is that 1m of capped plastic pipe floats vertically with 330mm immersed;
so, 7.5m capped pipe floats vertically with 2.5m immersed and 5m above the surface.